Grinding machine



J. N. HEALD ET AL GRINDING MACHINE Filed Aug; 1922 Patented Dec. 16, 1924.

UNITED STATES PATENT o Fic JAMES N. HEALD, ALDEN M. DRAKE. AND WALDO J'. GUILD, OF WORCESTER, MASSA- CHUSETTS, ASSIGNORS TO THE HEALD MACHINE COMPANY, OF WORCESTER,

MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

GRINDING MACHINE.

Application filed August 23, 1922. Serial No. 583,779.

To all whom it may concern-.-

Be it known that we, JAMES N. HEALD, ALDEN M. DRAKE, and lVALDo J. GUILD, all citizens of the United States, residing at lVorcester, in the county of 'Worcester and Commonwealth of Massachusetts, have invented a new and useful Improvement in a Grinding Machine, of which the following, together with the accompanying drawings, is a specification.

The present invention relates to grinding 'machines, and in particular, to the means employed in such a machine for procuring rotation of the grinding wheel and at the same time permitting the movement of said wheel over the surface of the work.

The invention resides in the several features of novelty hereinafter described in detail and specified in the-appended claims, reference being had to the accompanying drawings, wherein- Fig. 1 is a view in rear elevation showing a grinding machine embodying the invention.

Fig. 2 is an end view, partly in section, of said machine, and

Fig. 3 is a fragmentary sectional view, showing a detail of construction.

Like reference characters refer to like parts in the diiferent figures.

For purposes of illustration, the invention is here shown as applied to an internal grinder, the base 1 of which carries the usual head in which is journalled a rotatable work spindle 2. The latter serves for the support and rotation of the work, being driven at moderate speed by a belt 3, or in any other well known manner. The base 1 also provides longitudinal ways 4, 4 for the movement of a sliding table 5, which carries a rotating grinding wheel 6; the latters traverse of the rotating work, procures, in a manner well known in the art, a uniform grinding action, over the entire interior concave surface or hole.

The grinding wheel 6 is here shown as mounted on the end of a spindle 7, which moves with the table 5, being. driven at high speed by a belt 8. The belt 8 connects a pulley 9 on spindle 7 with a pulley 10-on a. countershaft 1 1, the latter, for the purpose of receiving a belt drive, being carried'at the rear of the machine and in overhanging relation to the base 1 and to the ways 4, =1

of table 5. In the particular machine herein illustrated, provision is made for a cross-feed of the grinding wheel 6 in a direction transverse to the line of movement of table 5, and to this end, the Wheel spindle 7 together with its driving pulleys 9 and 10 and belt 8, above described, is carried directly on a cross slide 12, the latter being adjustable transversely in suitable ways 13, 13 provided by the longitudinally movable table 5. The belt 8 is acted upon by a tightener pulley 11, carried by a rocker arm 15 and held yieldingly in contact with the belt by the action of a spring 16.

The invention contemplates a self-contained machine, wherein the belt drive for the overhanging countershaft 11, instead of being taken from overhead shafting, is taken from a drum 1? located preferably at the lower rear side of the machine, said drum being elongated to correspond to the longitudinal throw or travel of the table 5. The drum 17, carried by a driving shaft 18, receives rotation from any suitable source of power, such as a motor, not shown, and a belt 19, running in the direction 'shown by arrow A, Fig. 1, transmits the rotation of said drum to a pulley 20 on shaft 11; in the back and forth movement of table 5 carrying with itthe superposed driving mechanism for wheel spindle 7, said belt 19 tracks back and forth on the drum 17 and serves at all times for the transmission of power to the countershaft ll'and wheel spindle 7.

In the above described arrangement, there is necessarily considerable overhang of the shaft 11, on the rear of the machine, and this, coupled with the fact that the pull of belt 19 is downward, exerts, unless counteracted, a tipping tendency on the table 5, to rock it rearwardly, or at least, an excessive pressure between said table and its rear or right hand way 1. According to the invention, all downward belt pull on the table 5 is eliminated by the provision of means adapted to transfer said pull or strain directly onto the solid base 1 of the machine. Said means, as here shown, takes the form of a rail :21, rigidly secured to the rear side of the machine by means of bolts 22, 22, the latter entering suitable flanges 23, 23 of said base 1, which flanges are spaced apart, longitudinally, for approximately the length of drum 1?, so as to allow the free movement between them of the in the lower end of a follower member 25, which is secured by bolts 26, 26 .to the rear edge of table 5. Said bolts 26, as shown in Fig. 3, pass loosely and freely through apertures 27, 27 .of the follower member, and permit limited rocking movement of the I latter, relative to table 5, by the yielding of washers or springs 28 surrounding said I bolts; this eliminates any necessity for extreme accuracy in lining up the rail 21 with the ways 4, 4 in which the table 5 slides. The pressureof follower member on the extension of base 1, provided by rail 21, is substantially in vertical alinement with the axis of countershaft 11, the latter, as

shown in Fig. 1, being journalled in a yoke 29 that is pivoted at 30 to an upwardly extending bracket 31. of the cross'slide 12. The connection between the yoke 29 and the follower member 25, whereby the belt pull is transmitted to rail 21, takes the form of a two-part link 32, which is pivotally connected at 33 and 34, respectively, with the follower 25 and with a downward extension 35 of yoke 29. I

The expansive force of a spring 36 operates to distend the link 32, thus tending always to maintain the axis at the proper height for tautness in the belt 19. The downward pull of said belt onoverhanging shaft 11 is transmitted from extension 35, link 32 and follower 25 to the rail 21, said parts forming, by reason of the expansibility of link 32, a substantially straight line pressure transmitting member in each and every position assumed by the axis of shaft 11. In this way, the travelling table 5 is practically relieved of any pressure resulting from the downward'pull of belt 19 and thus, notwithstanding the over- .of shaft 11 hang of the. driving devices for wheel spindle 7, has no tendency either to tip up or to bind by excessive friction on the right hand slideway 4. The lateral changes of position to which the axis of shaft 11 is subjected, by reason of the adjustment of the cross-feed slide 12, are compensated for by the pivotal connections 33 and 34 of the pressure transmitting linkage, which pivotal connections permit said linkage to adjust itself automatically to the different posi tions without disturbing the essential pres sure transmit-ting relations between the several parts.

1. In a grinding machine, a base, a table supported on said base and adapted totravel longitudinally, a grinding wheel carried by said table, and movable crosswise thereof, a belt pulley for said wheel in overhanging relation to the table support, a drive pulley below said belt pulle whereby a downward pull is-exerted on the. belt pulley and table, and flexibly jointed pressure transmitting means for relieving said pull, whereby sai means is adapted to adjust itself to the crosswise movement of the wheel.

2. In a grinding machine, a base, a table slidable longitudinallyon said base, a grinding wheel carried by said table, a belt drive for said wheel having a driven member, a driving pulley below said driven member and yieldably extensible means, said driven member and adapted to receive the downward pull of said belt drive.

3. In a grinding. machine, a travelling table, a grinding wheel carried thereby, a

two-belt drive between said wheel and the pulleys of said twp-belt drive from the frame of the machine, and a follower member, having limited rocking movement relative to said table, to which said expansible connection is pivoted.

Dated this 19th day of August, 1922. JAMES ,N. HEALD.

ALDEN M. DRAKE. WALDO J. GUILD.

supporting 

